Evergreen Formation | |
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Stratigraphic range: Lower Pliensbachian- Late Toarcian ~ [1] | |
Type | Geological formation |
Unit of | Bundamba Group |
Sub-units | Boxvale Sandstone & Westgrove Ironstone Members |
Underlies | Hutton Sandstone |
Overlies | Precipice Sandstone |
Thickness | Up to 255 m (837 ft) |
Lithology | |
Primary | Sandstone, siltstone, mudstone |
Other | Coal, ironstone |
Location | |
Coordinates | 25°48′S150°18′E / 25.8°S 150.3°E |
Approximate paleocoordinates | 61°42′S90°00′E / 61.7°S 90.0°E |
Region | New South Wales Queensland |
Country | Australia |
Extent | |
Type section | |
Named for | "Evergreen Shales" |
Named by | Hogetoorn [3] |
The Evergreen Formation is a Pliensbachian to Toarcian geologic formation of the Surat Basin in New South Wales and Queensland, eastern Australia. Traditionally it has been considered to be a unit whose age has been calculated in between the Pliensbachian and Toarcian stages of the Early Jurassic, with some layers suggested to reach the Aalenian stage of the Middle Jurassic, yet modern data has found that an Early Pliensbachian to Latest Toarcian age is more possible. [4] [5] [6] The formation was named due to the "Evergreen Shales", defined with a lower unit, the Boxvale Sandstone, and a partially coeval, partially younger upper unit, the Westgrove Ironstone Member. [7] This unit overlies the Hettangian-Sinemurian Precipice Sandstone, as well several informal units such as the Nogo Beds, and Narayen beds, as well Torsdale Volcanics. [7] This unit likely was deposited in a massive lacustrine body with possible marine environment influences. [8]
Indeterminate Unionoid bivalves are know from the Kolane Station. [9]
Genus | Species | Type | Location | Material | Origin | Notes | Images |
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| Fodinichnia |
| Radiating bulb-like swelling burrows | Annelid worm, vermiform organism | Freshwater/Blackish burrow-like ichnofossils | ||
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| trails | Gastropods | Freshwater/Blackish fillings-like ichnofossils | |||
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| Long, subconical, weakly curved burrows |
| Freshwater/Blackish burrow-like ichnofossils | |||
| Domichnia | U-shaped burrows |
| Marine-Mangroove Vertical, U-shaped, single-spreite Burrows; unidirectional or bidirectional spreite, generally continuous, rarely discontinuous. Most Diplocraterion show only protrusive spreiten, like the local ones, produced under predominantly erosive conditions where the organism was constantly burrowing deeper into the substrate as sediment was eroded from the top. | |||
| Fodinichnia | Simple, unbranched, horizontal cylinder traces | Saltwater/Blackish burrow-like ichnofossils. | ||||
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| Dwelling traces |
| Marine, brackish or freshwater resting traces of Bivalves. | |||
| Fodinichnia | Straight to sinuous, unlined and unbranched burrows |
| Freshwater/Terrestrial burrow-like ichnofossils. | |||
| Domichnia | Straight or gently curved tubular burrows. |
| Freshwater/Blackish burrow-like ichnofossils. | |||
| Fodinichnia | Irregularly meandering burrows | Vermiform Animals | Freshwater burrow-like ichnofossils. | |||
| Pascichnia | Cylindrical or elliptical curved/tortuous trace fossils |
| Freshwater/Blackish burrow-like ichnofossils. Planolites is really common in all types of the Ciechocinek Formation deposits. It is referred to vermiform deposit-feeders, mainly Polychaetes, producing active Fodinichnia. It is controversial, since is considered a strictly a junior synonym of Palaeophycus . | |||
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| Symmetrical trail or burrow | Gastropods | Freshwater/Blackish trail-like ichnofossils | |||
| Domichnia | Cylindrical strands with branches |
| Blackish trace ichnofossils. Interpreted as dwelling structures of vermiform animals, more concretely the Domichnion of a suspension-feeding Worm or Phoronidan. | |||
| Domichnia | Cylindrical strands with branches |
| Blackish trace ichnofossils. Interpreted as dwelling structures of vermiform animals, more concretely the Domichnion of a suspension-feeding Worm or Phoronidan. | |||
| Fodinichnia | Unlined meniscate burrows |
| Freshwater/Blackish burrow-like ichnofossils. Taenidium is a meniscate backfill structure, usually considered to be produced by an animal progressing axially through the sediment and depositing alternating packets of differently constituted sediment behind it as it moves forward. | |||
| Tubular Fodinichnia | Tubular Burrows |
| Burrow-like ichnofossils. Large burrow-systems consisting of smooth-walled, essentially cylindrical components. Common sedimentary features are Thalassinoides trace fossils in the fissile marlstone to claystone intervals | |||
| Fodinichnia | Vertical to oblique, unbranched or branched, elongated to arcuate spreite burrow |
| Saltwater/Blackish burrow-like ichnofossils. The overall morphology and details of the burrows, in comparison with modern analogues and neoichnological experiments, suggest Echiurans (spoon worms) or Holothurians (sea cucumbers) with a combined suspension- and deposit-feeding behaviour as potential producers. | |||
Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
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| Westgrove Ironstone Member | Incomplete specimens: QMF12294, QMF12295 and one small fragment of a third specimen, QMF12296 | A millipede whose affinities are controversial. It may be an Oniscomorpha of the order Amynilyspedida family Amynilyspedidae or a member of the order Polydesmida | ||
Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
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Indeterminate |
| Westgrove Ironstone Member |
| A Freshwater Plesiosaur with affinities with Pliosauridae and Neoplesiosauria | ||
Siderops kehli |
| Westgrove Ironstone Member |
| A gigantic chigutisaurid temnospondyl, representing a relictual genus isolated in the Australian Ecoregion, as well one of the largest Mesozoic amphibians | ||
Genus | Species | Stratigraphic position | Material | Notes | Images |
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| Affinities with the family Zygnemataceae. A genus derived from freshwater filamentous or unicellular, uniseriate (unbranched) green algae. | ||
Genus | Species | Stratigraphic position | Material | Notes | Images |
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| Incertae sedis; affinities with Bryophyta. | ||
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| Incertae sedis; affinities with Bryophyta. | ||
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| Affinities with the family Sphagnaceae in the Sphagnopsida. | ||
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| Affinities with the family Notothyladaceae in the Anthocerotopsida. | ||
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| Incertae sedis; affinities with Bryophyta. This spore is found in Jurassic sediments associated with the polar regions. | ||
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| Affinities with the family Notothyladaceae in the Anthocerotopsida. Hornwort spores. | ||
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| Affinities with the family Sphagnaceae in the Sphagnopsida. | ||
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| Affinities with the family Sphagnaceae in the Sphagnopsida. "Peat moss" spores, related to genera such as Sphagnum that can store large amounts of water. | ||
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| Affinities with the family Encalyptaceae in the Bryopsida. Branching moss spores, indicating high water-depleting environments. | ||
Genus | Species | Stratigraphic position | Material | Notes | Images |
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| Affinities with the Selaginellaceae in the Lycopsida. | ||
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| Incertae sedis; affinities with Lycopodiopsida | ||
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| Affinities with the Selaginellaceae in the Lycopsida. Herbaceous lycophyte flora, similar to ferns, found in humid settings. This family of spores are also the most diverse in the formation. | ||
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| Affinities with the family Lycopodiaceae in the Lycopodiopsida. Lycopod spores, related to herbaceous to arbustive flora common in humid environments. | ||
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| Affinities with the family Lycopodiaceae in the Lycopodiopsida. Lycopod spores, related to herbaceous to arbustive flora common in humid environments. | ||
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| Affinities with the Selaginellaceae in the Lycopsida. | ||
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| Incertae sedis; affinities with Lycopodiopsida. | ||
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| Affinities with the family Lycopodiaceae in the Lycopodiopsida. | ||
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| Affinities with the family Lycopodiaceae in the Lycopodiopsida. Lycopod spores, related to herbaceous to arbustive flora common in humid environments. | ||
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| Affinities with the Selaginellaceae in the Lycopsida. | ||
Genus | Species | Stratigraphic position | Material | Notes | Images |
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| Affinities with the genus Saccoloma , type representative of the family Saccolomataceae . This fern spore resembles those of the living genus Saccoloma, being probably from a pantropical genus found in wet, shaded forest areas. | ||
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| Affinities with the family Osmundaceae in the Polypodiopsida. Near fluvial current ferns, related to the modern Osmunda regalis. | ||
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| Affinities with the Marattiaceae in the Polypodiopsida. Fern spores from low herbaceous flora. | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Affinities with the family Cyatheaceae in the Cyatheales. Arboreal fern spores. | ||
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| Affinities with the family Matoniaceae in the Gleicheniales. | ||
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| Affinities with the family Matoniaceae in the Gleicheniales. | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Affinities with the Gleicheniales in the Polypodiopsida. Fern spores from low herbaceous flora. | ||
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| Affinities with the Pteridaceae in the Polypodiopsida. Forest ferns from humid ground locations. | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Affinities with the family Dennstaedtiaceae in the Polypodiales. Forest fern spores. | ||
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| Affinities with the family Matoniaceae in the Gleicheniales. | ||
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| Affinities with the family Osmundaceae in the Polypodiopsida. Near fluvial current ferns, related to the modern Osmunda regalis. | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Incertae sedis; affinities with the Pteridophyta | ||
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| Affinities with the family Dennstaedtiaceae in the Polypodiales. Forest fern spores. | ||
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| Affinities with the family Osmundaceae in the Polypodiopsida. Near fluvial current ferns, related to the modern Osmunda regalis. | ||
Genus | Species | Stratigraphic position | Material | Notes | Images |
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| Affinities with the families Peltaspermaceae, Corystospermaceae or Umkomasiaceae in the Peltaspermales. Pollen of uncertain provenance that can be derived from any of the members of the Peltaspermales. The lack of distinctive characters and poor conservation make this pollen difficult to classify. Arboreal to arbustive seed ferns. | ||
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| Affinities with the families Peltaspermaceae, Corystospermaceae or Umkomasiaceae in the Peltaspermales. Extremely abundant | ||
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| From the family Caytoniaceae in the Caytoniales. Caytoniaceae are a complex group of Mesozoic fossil floras that may be related to both Peltaspermales and Ginkgoaceae. | ||
Genus | Species | Stratigraphic position | Material | Notes | Images |
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| Affinities with the family Cycadaceae in the Cycadales or with Cycadaceae and Bennettitaceae. It has been found associated with the Bennetite pollen cone Bennettistemon | ||
Genus | Species | Stratigraphic position | Material | Notes | Images |
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| Affinities with the family Araucariaceae in the Pinales. Conifer pollen from medium to large arboreal plants. | ||
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| Affinities with the family Araucariaceae in the Pinales. Conifer pollen from medium to large arboreal plants. | ||
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| Affinities with the Hirmeriellaceae in the Pinopsida. | ||
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| Affinities with the family Podocarpaceae inside Coniferae. | ||
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| Affinities with the family Cupressaceae in the Pinopsida. Pollen that resembles that of extant genera such as the genus Actinostrobus and Austrocedrus , probably derived from dry environments. | ||
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| Affinities with the family Podocarpaceae. Pollen from diverse types of Podocarpaceous conifers, that include morphotypes similar to the low arbustive Microcachrys and the medium arbustive Lepidothamnus , likely linked with Upland settings | ||
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| Affinities with the family Podocarpaceae. | ||
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| Affinities with the family Podocarpaceae. | ||
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| Affinities with the family Pinaceae in the Pinopsida. Conifer pollen from medium to large arboreal plants. | ||
The Surat Basin is a geological basin in eastern Australia. It is part of the Great Artesian Basin drainage basin of Australia. The Surat Basin extends across an area of 270,000 square kilometres and the southern third of the basin occupies a large part of northern New South Wales, the remainder is in Queensland. It comprises Jurassic through to Cretaceous aged sediments derived from Triassic and Permian arc rocks of the Hunter-Bowen orogeny. Towns situated above the basin, once dominated by agriculture, are experiencing a boom as mines and infrastructure in the area are expanded.
Siderops is an extinct genus of chigutisaurid temnospondyl from Early Jurassic of Australia, containing the species S. kehli.
The Kota Formation is a geological formation in India. The age of the Kota Formation is uncertain; it is commonly considered to date to the Early Jurassic, but some studies have suggested it may extend into the Middle Jurassic or even later. It conformably overlies the Lower Jurassic Upper Dharmaram Formation and is unconformably overlain by the Lower Cretaceous Gangapur Formation. It is split into a Lower Member and Upper Member. The Lower Member is approximately 100 m thick while the Upper Member is 490 m thick. Both subunits primarily consist of mudstone and sandstone, but near the base of the upper unit there is a 20-30 metre thick succession of limestone deposited in a freshwater setting.
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The Precipice Sandstone an Early Jurassic geologic formation of the Surat Basin in New South Wales and Queensland, eastern Australia, know due to the presence of abundant vertebrate remains & tracks. This unit includes the previously described Razorback beds. This unit represents a major, almost primary, source of hydrocarbons in the region, with a Potential CO2 reservoir of up to 70m. It was deposited on top of older sediments, like Bowen Basin units, in an unconformable manner, resting along the eastern basin margin and the Back Creek Group in the southern Comet Platform, while in other areas it directly overlies the Triassic Moolayember Formation & Callide Coal Measures, being deposited in a comparatively stable basin. Isopach maps of the Precipice Sandstone indicate two distinct areas of sediment accumulation, suggesting two separate depocentres filled from different source regions during the Sinemurian, with the Thomson orogeny and New England Orogen hinterlands as possible ones. This unit represented a fluvial-palustrine-lacustrine braided channel north-flowing succession, that seem to have debouch into a shallow restricted tidal/wave influenced marine embayment, marked at areas like Woleebee Creek. Paleoenvironment-wise, it represents a hinterland rich in vegetation, hinting at wet environments like swamps, where agglutinated foraminifera suggests marine flooding and drier conditions or the encroachment of seawater onto coastal areas.
The Cañadón Asfalto Formation is a geological formation from the Lower Jurassic, with doubtful layers of Late Jurassic age previously referred to it. The Cañadón Asfalto Formation is located in the Cañadón Asfalto Basin, a rift basin in the Chubut Province of northwestern Patagonia, southern Argentina. The basin started forming in the earliest Jurassic.
Geologically the Australian state of New South Wales consists of seven main regions: Lachlan Fold Belt, the Hunter-Bowen Orogeny or New England Orogen (NEO), the Delamerian Orogeny, the Clarence Moreton Basin, the Great Artesian Basin, the Sydney Basin, and the Murray Basin.
The Hasle Formation is a geologic formation on the island on Bornholm, Denmark. It is of early to late Pliensbachian age. Vertebrate fossils have been uncovered from this formation. The type section of the formation is found at the south of the costal Hasle Town, and it is composed by rusty yellow to brownish siltstones and very fine-grained sandstones. The southernmost arch, Hvjdoddebuen, is not as fossil-bearing as the type unit in Hasle. The formation can be separated in two different petrographic types: type 1 sandstones are friable with layers and lenses of concretionary siderite and type 2 well-cemented sandstones. Both types where deposited in a relatively high-energy marine environment with a diagenetic pattern that demonstrates a close relation to various phases of subsidence and uplift in the tectonically unstable Fennoscandian Border Zone. Most of its deposition happened on a storm-dominated shoreface, with the exposed parts deposited in an open marine shelf within 1–2 km distance from the fault-controlled coastlines. However, recent works have recovered terrestrial fauna from it, including a footprint, suggesting easterly winds and low tide could have exposed the inner parts of the upper shoreface, and create long-lasting Floodplain-type environments. Field works since 1984 have shown a mostly hummocky cross-stratified deposition, with great complexity of the sediments that suggests very complicated and variable flow conditions, with Megaripples derived from storm events. Storms were frequent and the coastline faced a wide epeiric sea with a fetch towards the west of possibly 1000 kilometers. The Jamesoni–Ibex Chronozone in the Central European Basin represents a clear sea Transgression, due to the appearance of ammonites from Thuringia and southern Lower Saxony, showing a full marine ingression towards the west. This rise in the sea level is also measured in the north, as is proven by the presence of Uptonia jamesoni in Kurremölla and Beaniceras centaurus plus Phricodoceras taylori on the Hasle Formation. The whole Hasle Sandstones are a result of this rise in the sea level, where the marine sediments cover the deltaic layers of the Rønne Formation. The rise in the sea level is observed on palynology, as on the Hasle Formation Nannoceratopsis senex (Dinoflajellate) and Mendicodinium reticulaturn appear, indicating a transition from paralic and restricted marine to fully marine.
The Cattamarra Coal Measures is an Early Jurassic geological unit in Western Australia.
The Drzewica Formation is a geologic formation in Szydłowiec, Poland. It is Pliensbachian in age. Vertebrate fossils have been uncovered from this formation, including dinosaur tracks. The Drzewica Formation is part of the Depositional sequence IV-VII of the late lower Jurassic Polish Basin, with the IV showing the presence of local Alluvial deposits, with possible meandriform deposition origin, dominated in Jagodne and Szydłowiec, while delta system occurred through the zone of the modern Budki. The sequence V shows a reduction of the erosion in the Zychorzyn borehole of the Drzewica Formation, showing changes on the extension of the marine facies, where upper deposits change from Alluvial to Deltaic-Seashore depositional settings. VI-VII facies were recovered on the Brody-Lubienia borehole, with a lower part exposed on the village of Śmiłów that shows a small fall of the Sea level. The stathigraphic setting of the dinosaur tracks reported from the formation suggest a Seashore or Deltaic barrier. Body fossils reported include bivalves, palynology, fossil trunks, roots. Trunks of coniferous wood, especially Cheirolepidiaceae and Araucariaceae trees show the occurrence of vast coniferous forests around the tracksite. The association of forests and dinosaur megafauna on the Pliensbachian suggests also a colder and specially dry ecosystem. Drzewica deposits where in part to be a gigantic shore barrel, setting at the time where the Polish basin sea was at its lowest point. Other related units are Fjerritslev or Gassum Formation, Hasle & Sorthat Formation (Bornholm), upper Neringa Formation (Lithuania) and abandoned informal units in other regions of Poland: upper Sawêcin beds, Wieluñ series or Bronów series.
The Ciechocinek Formation, known in Germany as the Green Series/Grimmen Formation is a Jurassic geologic formation that extends across the Baltic coast, from Grimmen, Germany, to Lithuania, with its major sequence in Poland and a few boreholes in Kaliningrad. It represents the largest continental area defined as deltaic in the fossil record, estimated to cover ~7.1 × 100,000 km2 (39,000 sq mi) only in the Polish realm. It is mostly known for its diverse entomofauna, composed of more than 150 species of different groups of insects, as well as its marine vertebrate fossils, including remains of sharks, actinopterygians and marine reptiles, along with terrestrial remains of dinosaurs, including the early thyreophoran Emausaurus and others not yet assigned to a definite genus. Its exposures are mostly derived from active clay mining of a dislocated glacial raft with exposed Upper Pliensbachian to late Toarcian shallow-marine sediments. Starting with coarse and fine sand deposits with concretions, the pure clay of the Ciechocinek Formation, after the falciferum zone, was deposited in a restricted basin south of the Fennoscandian mainland. It hosts a layer full of carbonate concretions, where a great entomofauna is recovered.
The Marne di Monte Serrone is a geological formation in Italy, dating to roughly between 181 and 178 million years ago, and covering the early and middle Toarcian stage of the Jurassic Period of central Italy. It is the regional equivalent to the Toarcian units of Spain such as the Turmiel Formation, units in Montenegro, such as the Budoš Limestone and units like the Tafraout Formation of Morocco.
The Budoš Limestone is a geological formation in Montenegro, dating to 180 million years ago, and covering the Toarcian stage of the Jurassic Period. It has been considered an important setting in Balkan paleontology, as it represents a unique terrestrial setting with abundant plant material, one of the few know from the Toarcian of Europe. It is the regional equivalent to the Toarcian units of Spain such as the Turmiel Formation, units like the Azilal Formation of Morocco and others from the Mediterranean such as the Posidonia Beds of Greece and the Marne di Monte Serrone of Italy. In the Adriatic section, this unit is an equivalent of the Calcare di Sogno of north Italy, as well represents almost the same type of ecosystem recovered in the older (Pliensbachian) Rotzo Formation of the Venetian region, know also for its rich floral record.
The Sorthat Formation is a geologic formation on the island of Bornholm, Denmark and in the Rønne Graben in the Baltic Sea. It is of Latest Pliensbachian to Late Toarcian age. Plant fossils have been recovered from the formation, along with several traces of invertebrate animals. The Sorthat Formation is overlain by fluvial to lacustrine gravels, along with sands, clay and in some places coal beds that are part of the Aalenian-Bathonian Bagå Formation. Until 2003, the Sorthat Formation was included as the lowermost part of the Bagå Formation, recovering the latest Pliensbachian to lower Aalenian boundary. The Sorthat strata reflect a mostly marginally deltaic to marine unit. Large streams fluctuated to the east, where a large river system was established at the start of the Toarcian. In the northwest, local volcanism that started in the lower Pliensbachian extended along the North Sea, mostly from southern Sweden. At this time, the Central Skåne Volcanic Province and the Egersund Basin expelled most of their material, with influences on the local tectonics. The Egersund Basin has abundant fresh porphyritic nephelinite lavas and dykes of lower Jurassic age, with a composition nearly identical to those found in the clay pits. That indicates the transport of strata from the continental margin by large fluvial channels of the Sorthat and the connected Röddinge Formation that ended in the sea deposits of the Ciechocinek Formation green series.
The Rya Formation is a geologic formation in Skåne County, southern Sweden. It is Early to early Middle Jurassic in age. The Rya Formation comprises siltstones, claystones, sandstones, mudstones and rare coal beds. The formation overlies the Höganäs Formation and is overlain by the Vilhelmsfält and Mariedal Formations.
The Djupadal Formation is a geologic formation in Skåne County, southern Sweden. It is Early Jurassic in age. It is part of the Central Skåne Volcanic Province, know by the discovery of basalt tuff layers, including Sandåkra, Korsaröd and Djupadal.
Joan Esterle is an American-Australian geologist who is an emeritus professor at school of Earth and Environmental Sciences from The University of Queensland, Australia and the chair of its Coal Geoscience Program.
The Röddinge Formation is a geologic formation in Skåne County, southern Sweden. It is Early Jurassic (Sinemurian-Toarcian) in age. It is a unit with a limited degree of exposure, being identified mostly by its deposits on the Fyledalen Fault Zone, specially on Kurremölla, where is present the main fossil deposit. It is a unit known mostly for large museum collections and estimated to have a thickness of several hundreds of meters. It is also known for its large iron deposits. It is correlated with the mostly marine Rya Formation of western Skåne County, the Volcanic deposits of the Djupadal Formation and specially the Sorthat Formation of Bornholm. Most likely, the coarse-grained nature of the Röddinge Formation is linked to rapid erosion of a tectonically active hinterland.
The Toarcian extinction event, also called the Pliensbachian-Toarcian extinction event, the Early Toarcian mass extinction, the Early Toarcian palaeoenvironmental crisis, or the Jenkyns Event, was an extinction event that occurred during the early part of the Toarcian age, approximately 183 million years ago, during the Early Jurassic. The extinction event had two main pulses, the first being the Pliensbachian-Toarcian boundary event (PTo-E). The second, larger pulse, the Toarcian Oceanic Anoxic Event (TOAE), was a global oceanic anoxic event, representing possibly the most extreme case of widespread ocean deoxygenation in the entire Phanerozoic eon. In addition to the PTo-E and TOAE, there were multiple other, smaller extinction pulses within this span of time.
The Tafraout Group is a geological group of formations of Toarcian-Aalenian age in the Azilal, Béni-Mellal, Imilchil, Zaouiat Ahansal, Ouarzazate, Tinerhir and Errachidia areas of the High Atlas of Morocco. The Group represents the remnants of a local massive Siliciclastic-Carbonate platform, best assigned to succession W-E of alluvial environment occasionally interrupted by shallow marine incursions and inner platform to open marine settings, and marks a dramatic decrease of the carbonate productivity under increasing terrigenous sedimentation. Fossils include large reef biotas with richness in "lithiotid" bivalves and coral mounts, but also by remains of vertebrates such as the sauropod Tazoudasaurus and the basal ceratosaur Berberosaurus, along with several undescribed genera. While there have been attributions of its lowermost layers to the Latest Pliensbachian, the current oldest properly measured are part of the Earliest Toarcian regression ("MRST10"), part of the Lower-Middle Palymorphum biozone. This group is composed of the following units, which extend from west to east: the Azilal Formation ; the Amezraï Formation ; the Aguerd-nˈTazoult Formation ; the Tagoudite Formation & the Trafraout Formation. They are connected with the offshore Ait Athmane Formation and the deeper shelf deposits of the Agoudim 1 Formation. Overall, this group represents a mixed carbonate-siliciclastic system of several hundred meters thick, dominated by deposits of shallow marine platforms linked to a nearby hinterland dominated by conglomerates. The strata of the group extend towards the central High Atlas, covering different anticlines and topographic features along the mountain range.